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author | Steve Block <steveblock@google.com> | 2011-05-13 06:44:40 -0700 |
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committer | Android (Google) Code Review <android-gerrit@google.com> | 2011-05-13 06:44:40 -0700 |
commit | 08014c20784f3db5df3a89b73cce46037b77eb59 (patch) | |
tree | 47749210d31e19e6e2f64036fa8fae2ad693476f /Source/JavaScriptCore/wtf/text/StringBuilder.cpp | |
parent | 860220379e56aeb66424861ad602b07ee22b4055 (diff) | |
parent | 4c3661f7918f8b3f139f824efb7855bedccb4c94 (diff) | |
download | external_webkit-08014c20784f3db5df3a89b73cce46037b77eb59.zip external_webkit-08014c20784f3db5df3a89b73cce46037b77eb59.tar.gz external_webkit-08014c20784f3db5df3a89b73cce46037b77eb59.tar.bz2 |
Merge changes Ide388898,Ic49f367c,I1158a808,Iacb6ca5d,I2100dd3a,I5c1abe54,Ib0ef9902,I31dbc523,I570314b3
* changes:
Merge WebKit at r75315: Update WebKit version
Merge WebKit at r75315: Add FrameLoaderClient PageCache stubs
Merge WebKit at r75315: Stub out AXObjectCache::remove()
Merge WebKit at r75315: Fix ImageBuffer
Merge WebKit at r75315: Fix PluginData::initPlugins()
Merge WebKit at r75315: Fix conflicts
Merge WebKit at r75315: Fix Makefiles
Merge WebKit at r75315: Move Android-specific WebCore files to Source
Merge WebKit at r75315: Initial merge by git.
Diffstat (limited to 'Source/JavaScriptCore/wtf/text/StringBuilder.cpp')
-rw-r--r-- | Source/JavaScriptCore/wtf/text/StringBuilder.cpp | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/wtf/text/StringBuilder.cpp b/Source/JavaScriptCore/wtf/text/StringBuilder.cpp new file mode 100644 index 0000000..dfc9ff3 --- /dev/null +++ b/Source/JavaScriptCore/wtf/text/StringBuilder.cpp @@ -0,0 +1,172 @@ +/* + * Copyright (C) 2010 Apple Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "config.h" +#include "StringBuilder.h" + +#include "WTFString.h" + +namespace WTF { + +void StringBuilder::reifyString() +{ + // Check if the string already exists. + if (!m_string.isNull()) { + ASSERT(m_string.length() == m_length); + return; + } + + // Check for empty. + if (!m_length) { + m_string = StringImpl::empty(); + return; + } + + // Must be valid in the buffer, take a substring (unless string fills the buffer). + ASSERT(m_buffer && m_length <= m_buffer->length()); + m_string = (m_length == m_buffer->length()) + ? m_buffer.get() + : StringImpl::create(m_buffer, 0, m_length); +} + +void StringBuilder::resize(unsigned newSize) +{ + // Check newSize < m_length, hence m_length > 0. + ASSERT(newSize <= m_length); + if (newSize == m_length) + return; + ASSERT(m_length); + + // If there is a buffer, we only need to duplicate it if it has more than one ref. + if (m_buffer) { + if (!m_buffer->hasOneRef()) + allocateBuffer(m_buffer->characters(), m_buffer->length()); + m_length = newSize; + m_string = String(); + return; + } + + // Since m_length && !m_buffer, the string must be valid in m_string, and m_string.length() > 0. + ASSERT(!m_string.isEmpty()); + ASSERT(m_length == m_string.length()); + ASSERT(newSize < m_string.length()); + m_length = newSize; + m_string = StringImpl::create(m_string.impl(), 0, newSize); +} + +void StringBuilder::reserveCapacity(unsigned newCapacity) +{ + if (m_buffer) { + // If there is already a buffer, then grow if necessary. + if (newCapacity > m_buffer->length()) + allocateBuffer(m_buffer->characters(), newCapacity); + } else { + // Grow the string, if necessary. + if (newCapacity > m_length) + allocateBuffer(m_string.characters(), newCapacity); + } +} + +// Allocate a new buffer, copying in currentCharacters (these may come from either m_string +// or m_buffer, neither will be reassigned until the copy has completed). +void StringBuilder::allocateBuffer(const UChar* currentCharacters, unsigned requiredLength) +{ + // Copy the existing data into a new buffer, set result to point to the end of the existing data. + RefPtr<StringImpl> buffer = StringImpl::createUninitialized(requiredLength, m_bufferCharacters); + memcpy(m_bufferCharacters, currentCharacters, static_cast<size_t>(m_length) * sizeof(UChar)); // This can't overflow. + + // Update the builder state. + m_buffer = buffer.release(); + m_string = String(); +} + +// Make 'length' additional capacity be available in m_buffer, update m_string & m_length, +// return a pointer to the newly allocated storage. +UChar* StringBuilder::appendUninitialized(unsigned length) +{ + ASSERT(length); + + // Calcuate the new size of the builder after appending. + unsigned requiredLength = length + m_length; + if (requiredLength < length) + CRASH(); + + if (m_buffer) { + // If the buffer is valid it must be at least as long as the current builder contents! + ASSERT(m_buffer->length() >= m_length); + + // Check if the buffer already has sufficient capacity. + if (requiredLength <= m_buffer->length()) { + unsigned currentLength = m_length; + m_string = String(); + m_length = requiredLength; + return m_bufferCharacters + currentLength; + } + + // We need to realloc the buffer. + allocateBuffer(m_buffer->characters(), std::max(requiredLength, m_buffer->length() * 2)); + } else { + ASSERT(m_string.length() == m_length); + allocateBuffer(m_string.characters(), std::max(requiredLength, requiredLength * 2)); + } + + UChar* result = m_bufferCharacters + m_length; + m_length = requiredLength; + return result; +} + +void StringBuilder::append(const UChar* characters, unsigned length) +{ + if (!length) + return; + ASSERT(characters); + + memcpy(appendUninitialized(length), characters, static_cast<size_t>(length) * 2); +} + +void StringBuilder::append(const char* characters, unsigned length) +{ + if (!length) + return; + ASSERT(characters); + + UChar* dest = appendUninitialized(length); + const char* end = characters + length; + while (characters < end) + *(dest++) = *(const unsigned char*)(characters++); +} + +void StringBuilder::shrinkToFit() +{ + // If the buffer is at least 80% full, don't bother copying. Need to tune this heuristic! + if (m_buffer && m_buffer->length() > (m_length + (m_length >> 2))) { + UChar* result; + m_string = StringImpl::createUninitialized(m_length, result); + memcpy(result, m_buffer->characters(), static_cast<size_t>(m_length) * 2); // This can't overflow. + m_buffer = 0; + } +} + +} // namespace WTF |